A Novel Photocatalytic Conversion of Tryptophan to Kynurenine Using Black Light as a Light Source

Hamdy, Mohamed S.; Scott, Elinor L.; Carr, R. H.; Sanders, J.P.M.

doi:10.1007/s10562-012-0775-7

Cited by 28 publications

(13 citation statements)

References 50 publications

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“…161 Alternatively, TiO 2 can be used to photo-deformylate tryptophan into kynurenine under black light with up to 90 mol% selectivity. 162 Kynurenine can be used to produce alanine and, by further decarboxylation over zeolite catalysts, bio-based aniline. 163 …”

Section: Titanium Dioxide Photodecarboxylationmentioning

confidence: 99%

Deoxygenation of biobased molecules by decarboxylation and decarbonylation – a review on the role of heterogeneous, homogeneous and bio-catalysis

et al. 2015

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Use of biomass is crucial for a sustainable supply of chemicals and fuels for future generations. Compared to fossil feedstocks, biomass is more functionalized and requires defunctionalisation to make it suitable for use. Deoxygenation is an important method of defunctionalisation. While thermal deoxygenation is possible, high energy input and lower reaction selectivity makes it less suitable for producing the desired chemicals and fuels. Catalytic deoxygenation is more successful by lowering the activation energy of the reaction, and when designed correctly, is more selective. Catalytic deoxygenation can be performed in various ways. Here we focus on decarboxylation and decarbonylation. There are several classes of catalysts: heterogeneous, homogeneous, bio-and organocatalysts and all have limitations. Homogeneous catalysts generally have superior selectivity and specificity but separation from the reaction is cumbersome. Heterogeneous catalysts are more readily isolated and can be utilised at high temperatures, however they have lower selectivity in complex reaction mixtures. While bio-catalysts can operate at ambient temperatures, the volumetric productivity is lower. Therefore it is not always apparent in advance which catalyst is the most suitable in terms of conversion and selectivity under optimal process conditions. Here we compare classes of catalysts for the decarboxylation and decarbonylation of biobased molecules and discuss their limitations and advantages. We mainly focus on the activity of the catalysts and find there is a strong correlation between specific activity (turn over frequency) and temperature for metal based catalysts (homogeneous or heterogeneous). Thus one is not more active than the other at the same temperature. Alternatively, enzymes have a higher turnover frequency but drawbacks (low volumetric productivity) should be overcome.

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Section: Titanium Dioxide Photodecarboxylationmentioning

confidence: 99%

Deoxygenation of biobased molecules by decarboxylation and decarbonylation – a review on the role of heterogeneous, homogeneous and bio-catalysis

et al. 2015

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“…Other studies have demonstrated that these metabolites are major ultraviolet-photooxidation products of tryptophan (76). Hamdy et al exposed tryptophan to various light sources and demonstrated that UVB light markedly increased metabolism along this pathway (77). Sheipouri et al have shown that UV skin damage correlates with production of kynurenines from tryptophan (78).…”

Section: Tryptophan Fluorescencementioning

confidence: 99%

The Mystery of Chemotherapy Brain: Kynurenines, Tubulin and Biophoton Release

Sordillo

2020

Anticancer Res

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The majority of patients receiving chemotherapy experience post-chemotherapy cognitive impairment, sometimes referred to as "chemo brain" or "chemo fog." The cognitive impairment associated with this syndrome can be severe, and can sometimes last for many years after therapy discontinuation. Despite extensive investigations, its etiology is unknown. We argue that chemo brain results from damage to tubulin within microtubules. This damage can occur directly from tubulin inhibitors such as taxanes, epothilones or vinca alkaloids. Other chemotherapies stimulate increased mitochondrial activity and biophoton release. This results in abnormal tryptophan metabolism and excess production of neurotoxic kynurenines, which, in turn, damage microtubules.

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“…23 The photocatalytic decomposition of tryptophan has also been reported to produce kynurenine. 24 In 2006, Ferrini et al 25 reported the preparation of 2-aryl amines in high yields by photochemical rearrangement of aromatic amides when they were irradiated with UV light. Cbz-tryptophan has been used to prepare L-kynurenine upon reaction with the oxidizing mixture of DMSO/HCl in AcOH, followed by additional oxidation with air (Scheme 2F).…”

Section: Paper Synthesismentioning

confidence: 99%

Synthesis of l-Kynurenine and Homo-l-Kynurenine via an Aza-Fries Rearrangement

2020

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l-Kynurenine, a non-proteinogenic amino acid, is the primary metabolite of tryptophan via the kynurenine pathway. Kynurenine is involved in a variety of biological processes occurring in the human body, notably in the central nervous system. Thus, the study of this molecule offers multiple opportunities for drug discovery; however, an essential prelude for biological studies is to secure the supply of kynurenine and analogues thereof. A simple synthetic procedure for the efficient preparation of enantiomerically pure l-kynurenine from l-aspartic acid and its implementation to prepare homo-l-kynurenine from l-glutamic acid is presented. The approach relies on a photochemical aza-Fries rearrangement of the corresponding acyl-aniline as the fundamental transformation.

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A Novel Photocatalytic Conversion of Tryptophan to Kynurenine Using Black Light as a Light Source

Cited by 28 publications

References 50 publications

Deoxygenation of biobased molecules by decarboxylation and decarbonylation – a review on the role of heterogeneous, homogeneous and bio-catalysis

Deoxygenation of biobased molecules by decarboxylation and decarbonylation – a review on the role of heterogeneous, homogeneous and bio-catalysis

The Mystery of Chemotherapy Brain: Kynurenines, Tubulin and Biophoton Release

Synthesis of l-Kynurenine and Homo-l-Kynurenine via an Aza-Fries Rearrangement

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